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After years of friendship and many hours hanging out together, I knew my feelings for Heidi had grown beyond merely "being in like"—the truth is, I was really in love with her!

Was Heidi in love with me—enough to be willing to become my wife? That's what I was about to find out. I felt fairly confident, but as any guy in my shoes knows, until you actually hear her say "yes," you live with a certain amount of trepidation and doubt.

When the moment came, I worked up the nerve and blurted out the question. Heidi's reply? After a brief hesitation—one that felt like a million years—she agreed to marry me! I don't want to imply that I was excited, but the fact that I shouted, "She said YES!" over and over probably gives away my true feelings.

Was our love real? It certainly seemed to be on that day. As it did on the day of our wedding. And when each of our kids was born. And when Heidi brought me freshly brewed coffee this morning. After more than twenty-five years of marriage, I think we've made a pretty strong case: our love for each other is genuine.

Love is not a physical entity, and yet it's very real. In fact, for those who are in love, it can be more real than the world around them! But in order to know if there is true love in a particular situation, sometimes we need evidence. And being the skeptic that I am, I needed fairly strong evidence.

In my relationship with Heidi, evidence of her love emerged along the way—she wrote me notes that reflected her affection; she spent hours with me on the phone; she seemed to enjoy being around me; she even gave me loving looks sometimes. Then there was the big day when she agreed to marry me. While each one of these actions pointed to her love for me, taken together they provided overwhelming confirmation. I could put it like this: the cumulative evidence was more than enough to believe that Heidi's love for me was the real deal.

But can I prove it to you? Can I show you our love for each other in a tangible way—one that you can see, hear, or touch? No, the love itself is invisible. It's one of those things that you have to detect through its effects. Much like air: You can't see it (unless you're in downtown Los Angeles), but you can breathe it, experience it, and move in it. Or like gravity—it's not visible, but you'd better not try to ignore it!

One of the most important issues that surfaced in the survey we talked about in the introduction—in fact, tied for first place as the question respondents most hoped nobody would ask them—was this: how can you know there's a God? He's not tangible; you can't weigh him, measure him, touch him, or see him with the naked eye—or detect him with radar, for that matter! His presence doesn't register with any of our senses, and yet you believe in him. Why?

It's a challenging question that's obviously central to all we believe as followers of Christ. So how can we respond?

First, we can point out to our friend, as I did above, that there are plenty of important things we believe in without seeing, hearing, or touching them. Love, as I've explained, is a profound reality, and most of us believe in love. But love itself is not a material thing. It's not something we can see, hear, or touch directly.

The Christian understanding is that God is not a material thing either. This is clear in John 4:24, in which Jesus tells us "God is Spirit." Unlike my friends, my dog Charlie, my iPod, or my mountain bike—all of which I can see, hear, and touch because they are physical, material things—God is a spiritual being or reality, and spiritual realities are not the kinds of things that can be seen with physical eyes or heard with physical ears or touched with physical hands. So I guess we shouldn't really be surprised that we can't experience God in the same way we can experience those other things.

A Personal Response

But that's not to say we don't experience God in other ways. If you are one of his true followers, you have experienced him on a personal level, and I trust you sense his presence and work in your life on at least a periodic basis. I know that years ago in my own life I felt God's touch on me in numerous ways, leading up to the point at which I put my trust in Christ. Some of those "touches" were wake-up calls in which he showed me the dead-end path my life was on, convicted me of sins, and revealed that I was made for much greater purposes than I was experiencing at the time.

Then, when I finally gave in to what I'm confident was the Holy Spirit drawing me to trust and follow Christ, I sensed his forgiveness and his acceptance as God's newly adopted son. That squared with what I later read in Romans 8:15-16, where Paul says, "You received God's Spirit when he adopted you as his own children. Now we call him, ‘Abba, Father.' For his Spirit joins with our spirit to affirm that we are God's children."

And since that time I often know, in hard-to-explain and internal ways, that God is prompting me to speak to a person, send an encouraging note, challenge a wayward brother in the faith, or pray for someone in need. And occasionally I sense him guiding me in bigger life decisions regarding my work, ministry involvements, moves to new locales, and so forth. These leadings don't come every day, but there's a marked pattern of them in my life—they've had a huge influence in my overall direction and impact.

I share some of these details to show that one of the ways I know God is real and active in our world is that he's real and active in my life, and I'm guessing you'd say the same thing if you're a committed Christian. If so, then that's a natural part of our answer to people who ask us this question about God's existence. We know he exists because he's our friend! He has forgiven us and turned our lives around, and he speaks to us, guides us, redirects us, and rebukes us when we need it (see Heb. 12:5-12)—always acting out of love for us and what's best for our lives. So one point we can make is our humble acknowledgment of his presence and activity in our daily experience.

Our testimony alone can have a powerful influence on others, especially those who know us well and are therefore inclined to trust what we say. It can also influence those who have seen clear evidence of God's work in us—they can't see him, but they can see what he's done in our lives.

Experience is hard to argue with. That's why the ­apostle Paul often appealed to it, as did other biblical writers. He said to his skeptical listeners in Acts 26:12-16, for example, "One day I was on such a mission to Damascus. . . . A light from heaven brighter than the sun shone down on me. . . . I heard a voice saying to me in Aramaic, ‘Saul, Saul, why are you persecuting me? . . . I am Jesus, the one you are persecuting. Now get to your feet! For I have appeared to you to appoint you as my servant and witness.'" Paul went on from there and gave further details, but it's clear that his account of God's activity in his life made an impact. Agrippa, one of his listeners, interrupted and asked him, "Do you think you can persuade me to become a Christian so quickly?" (v. 28). To which Paul, the consummate evangelist, winsomely replied, "Whether quickly or not, I pray to God that both you and everyone here in this audience might become the same as I am" (v. 29).

Telling others about God's activity in our lives can be a powerful tool, but many people will not be convinced by that alone. They might conclude that you're sincere—but that you're mistaking coincidences in your life for supernatural interventions. And some people may even question your sincerity. So let's explore some other ways we can point to the effects of the invisible God in our world by using examples that everyone can access. For the rest of this chapter we'll look at three of the best examples of evidence for God's existence that we can share with our friends: two that are scientific and one that is more philosophical in nature. (Note that other powerful kinds of evidence could be given to support belief in the Christian God, including those from history, archaeology, and the records of prophecies and miracles preserved in the Bible. I do so in my book Choosing Your Faith . . . In a World of Spiritual Options,1 where I pre­sent twenty arguments for the Christian faith. Some of that information will come out naturally as we address the other questions in this book.)

As I've been exploring these matters for the last twenty-five years or so, I've come to believe that today, perhaps more than in any other period of human history, the fingerprints of God have become exceedingly evident for anyone who is willing to search for them. Each of these arguments is power­ful on its own and has convinced many people of the reality of God. But when considered together, along with our own testimonies of experiencing him in our daily lives, the cumulative case is staggering.

Evidence #1: The Existence of the Universe

Throughout history, many people have supposed that the universe always existed. A number of famous ancient thinkers from the East (such as Lao Tzu, a central figure in the Taoist religion) and the West (such as Aristotle) believed that the universe is eternal—in other words, that it never had a beginning. This was a fairly prevalent view among philosophers and scientists up until the twentieth century. They had their reasons for believing this, but there was no effective way to either confirm or disconfirm their beliefs—until recently.

Fortunately, in the last several decades there has been an exponential growth of understanding in many areas of science, especially in physics, astronomy, and cosmology. This third area, cosmology—which is the study of the origin, structure, and development of the physical universe—has seen explosive advancements in recent years. Let's look at one example.

In 1915, Albert Einstein developed the general theory of relativity (which is far too complex to explain in this chapter, even if I could fully explain it!). This theory, which is now almost universally accepted, has certain implications. One is that the universe—defined as time, space, matter, and physical energy—had a starting point in history. And, since it had a beginning, it's not eternal as Lao Tzu and Aristotle believed. As a matter of fact, through Einstein's equations we can trace the development of the universe back to its very origin, back to what's called the singularity event when it actually popped into being (what is often referred to as the "Big Bang").

Now, many scientists and others, including Einstein himself, didn't like this result (perhaps because it sounded too much like the biblical account of Creation?). So they tried to find an error in the equations—one that would allow for the universe to be understood as eternal after all. But they didn't succeed. And recent experimental observations have provided even more support showing that Einstein had it right: the universe really did have a beginning.

One of the scientific confirmations of Einstein's theory was provided by the Hubble Space Telescope, named after American astronomer Edwin Hubble. This impressive telescope allowed astronomers to see that the universe is actually expanding—and the farther away the galaxy is, the faster it's moving. This led most scientists to further reinforce their conclusion that the universe had a beginning point from which it began this expansion process.

So how does this Hubble confirmation of the origin of the universe provide evidence for God? Great question! Here's how: if the universe had a starting point in history, then obviously it began to exist. But if it began to exist, then it must have had a cause for its existence. Things don't just begin to exist without a cause. Science itself operates on the principle that all events need a cause. As Einstein once declared, "The scientist is possessed by a sense of universal causation."

But if the universe needs a cause for its coming into being, then that cause must be beyond the universe. As we saw earlier, the universe—by definition—is time, space, matter, and physical energy. So the cause for the universe must be something beyond time and space and matter and physical energy. In other words, the cause must be something uncannily similar to what we commonly refer to as "God"!

Before completely landing on this conclusion, let's look at an objection to it. My friend Chad Meister, who has his doctorate in philosophy and teaches philosophy of religion at the graduate level, told me a story about what happened to him awhile back at a dinner with his wife and others from the company where she was an accountant. The firm was celebrating the end of tax season and had invited the employees and their spouses for a nice dinner at a five-star restaurant. Chad happened to sit next to a pilot for a major airline. As they ate, the conversation eventually came around to spiritual matters, and the pilot said he didn't believe in God—which is not a very good position to take when you're having dinner with the likes of Dr. Meister!

Chad brought up this cosmological evidence from the Hubble telescope, and the pilot responded, "Yes, but how do you know it is God who created the universe? Maybe an alien did the creating!" Chad replied, "Maybe so! But let's keep in mind that our alien, whom we can call Bob, is timeless (that is, outside of time), nonspatial (outside of the spatial dimension), immaterial (not made up of any matter), and does not consist of physical energy, yet was powerful enough to create the entire universe—all the billions and billions of galaxies, each of which has billions and billions of stars. In light of that information, you can call him Bob, but I call him Yahweh! This is the transcendent God beyond space and time in whom Christians have believed for two thousand years."

Can you see how powerful this information is—even when people try to escape it with clever stories about things like aliens or elves? Even Richard Dawkins, probably the most prominent proponent for atheism of our times, admitted in an article in Time magazine that "there could be something incredibly grand and incomprehensible and beyond our present understanding." When challenged with "That's God!" he replied, "Yes. But it could be any of a billion Gods. It could be God of the Martians or of the inhabitants of Alpha Centauri. The chance of its being a particular God, Yahweh, the God of Jesus, is vanishingly small."

Against that kind of a diversion we can say, "You can call him what you want, but the evidence from the origin of the universe tells us a lot about what he is like—and the description sounds amazingly similar to what the Bible tells us about one particular God, who actually is called Yahweh, the God of Jesus, the Creator of the world."

It's worth noting that the initial reaction of some Christians to the very idea of the Big Bang at the beginning of the universe is negative—but I don't think this is necessary. Yes, many scientists hold that this event was completely natural, unaided by any outside force or intelligence (such as God). But as we've seen, the evidence is against them. The event itself calls for a cause outside of the universe—one that is wise and powerful enough to be able to pull it off. That's why Einstein and many other thinkers in his day and since then have resisted the idea of the Big Bang—they didn't like the theological implications that came with it. But from a Christian point of view, the Big Bang sounds like an awfully compelling scientific description of the biblical doctrine of creation ex nihilo—"out of nothing."

One other objection that frequently comes up is this: "Well, if everything needs a cause, then who caused God?" But this is a misunderstanding of the argument itself, which does not say that everything needs a cause—just everythingthat has a beginning needs a cause! Science shows, through Einstein's calculations and Hubble's telescope, among other things, that the universe had a beginning—therefore the universe needs a cause. And that cause is the immaterial, eternal God of the universe, who had no beginning and who therefore does not have or need a cause.

We can summarize this cosmological evidence into a concise series of statements:

1. Whatever begins to exist must have a cause for its existence. 2. The universe began to exist. 3. Therefore, the universe must have a cause for its existence. 4. The attributes of the cause of the universe (being timeless, existing outside of space, and so on) are the attributes of God. 5. Therefore, the cause of the universe must be God.

This is precisely what Christians have always believed. The very first words of the Bible, in the book of Genesis, declare, "In the beginning God created the heavens and the earth." In spite of what many people have heard, science is not at odds with belief in God. To the contrary, science actually provides compelling evidence for God's existence!

Evidence #2: Our "Just So" Universe

The more I watch the Discovery Channel and read about the amazing intricacies of our world, the more amazed I am at the beauty and complexity of it all. I often ride my mountain bike along the trails near where I live. Sometimes I stop and admire the unique plants growing along the hillsides or down in the ravines; other times I'll enjoy the surprise of an unexpected deer, coyote, or fox as it runs out in front of me. Often I'll reflect on a sunset showering down brilliant colors of red, yellow, and orange. I'm regularly taken aback by what I see. I think often about how much I relate to the psalmist when he says, "The heavens proclaim the glory of God. The skies display his craftsmanship" (Ps. 19:1).

But here's what is amazing: this incredible array of life and beauty and complexity did not spring into existence unaided. Rather, what cutting-edge science is now telling us is that the building blocks of our world—the laws and physical constants that govern all the matter in the universe—appear to be precisely balanced and finely tuned for life to occur and flourish.

These laws and constants were set at the singularity event mentioned earlier. In other words, when the universe exploded into being—the Big Bang—there were a number of variables within the very structure of the universe itself that had to be set exactly as they are in order for life to exist. Scientists have so far discovered about fifty of these parameters and constants that must be "just so" in order for life to be possible anywhere in the universe.

Let's hone in on one particular example of this "fine-tuning." Physicists have discovered four forces in nature, and one of them is the force of gravity. Physicists have calculated that the strength of each of these forces must fall within a very specific range or there would be no conscious life possible. If the force of gravity, for example, were to change by one part in ten thousand billion billion billion relative to the total range of the strengths of the four forces in nature, conscious life would be virtually impossible anywhere in the universe.

There are many other parameters and constants that are also finely tuned and that, if changed even slightly, would have disastrous consequences for life in our universe. For example, if the neutron were not exactly as it is—about 1.001 times the mass of the proton—then all protons would have decayed into neutrons or all neutrons would have decayed into protons, and life would not be possible. If the explosion of the Big Bang had differed in strength by as little as one part in 1060 (one part in a trillion trillion trillion trillion trillion), the universe would have either quickly collapsed back on itself or expanded too swiftly for stars to form. Either way, life would be impossible. The list goes on and on.

What makes all this even more fascinating is that these finely tuned parameters and constants are independent of one another. In other words, they could all be just right for life except for one, which is off to the smallest degree—and that alone would have precluded me from existing to write this and you from existing to read it. This makes it yet more unlikely that they all came to be just so by chance. In fact, because of this evidence Paul Davies, one of the leading physicists and cosmologists of our day, makes this audacious claim: "I cannot believe that our existence in this universe is a mere quirk of fate. . . . We are truly meant to be here."9 That's quite a statement for one who doesn't even claim to believe in a personal God!

In addition to the parameters and constants necessary for life in the universe, there are also fascinating characteristics of a planet that are necessary for it to support complex life. Recent discoveries demonstrate that there are at least two dozen such characteristics that must be in place for life to be possible on a planet. These include its consisting of the correct mass; being orbited by a large moon, having a magnetic field; manifesting an oxygen-rich atmosphere; orbiting a main-sequence, G2 dwarf star; and being in the correct location in the galactic habitable zone. Each of these factors has to occur in the right place at the right time with respect to the same planet in order for complex life to even be a possibility there. The probability of these factors converging is so infinitesimally small that many cosmologists and astrophysicists now admit that it's more reasonable to believe that a divine designer was involved than to assume it all happened by chance.

Of course, not everyone is happy with this conclusion. Some are working overtime to find alternative theories to explain these phenomena without divine intervention. In fact, there are a few serious objections that we should address. The first is that these highly unlikely events can be explained without God if a very large number of universes exist besides our own, each with its own parameters and constants. If there are a very large number of universes and they were all produced randomly, most of them would surely include parameters that are life prohibiting. But if the number of universes is large enough—maybe infinite—then some of them, by sheer chance, might have just the right parameters for life. Luckily for us, the argument goes, our universe happens to be one that has the right parameters.

One big problem with this objection is that there is no scientific evidence that it is true or even possible. It's purely speculative. Science fiction writers are having a heyday with the idea, but the scientific facts are lacking, to say the least.

Another problem is that if there are an infinite number of universes, then those must have been produced by some kind of a "many-universe generator." But this generator itself must be a very sophisticated device in order to produce countless universes. I mean, even my toaster needs to be well designed to toast bread (though I'm not so sure it was really well designed, since it often pops my toast onto the kitchen floor!). How much more so a universe maker who produces countless universes, including finely tuned ones like our own. What kind of an incredible intelligence could account for such an astounding machine or process such as that?

Yet another objection I often hear is this: if the evidence points to a divine designer, then who designed the designer? If we don't need to answer that question, it's argued, then why do we need to worry about a designer of our universe? While this is an interesting challenge, it misses the simple point that the universe is better explained by design than by chance.

Consider this example: suppose you went on a deep-sea expedition and came upon what seemed to be an under­water city. It was unique, like nothing you'd ever seen before. Suppose there were structures apparently designed to sustain oxygen-breathing creatures (like us), including rooms from which water could be evacuated, long tubelike tunnels that could pump in oxygen from above the water, and various inlets that could be used for transportation purposes.

In this scenario, it would seem far more reasonable to believe that there was a designer who created this place than to suppose that it came into being purely by chance. But we would not need to forgo the claim that an intelligent being designed the city just because that intelligent being itself may be in need of further explanation. So the question of whether or not God needs further explanation, though an interesting one, has no bearing on this argument about our finely tuned universe.

So our argument stands: the incredible confluence of the many examples of fine-tuning in the universe—each independently set to the precise measures necessary to support life—points powerfully to the existence of an incredibly intelligent designer who made it all "just so" . . . for us!

Or, as Isaiah 40:25-26, 28 puts it,

"To whom will you compare me? Who is my equal?" asks the Holy One. Look up into the heavens. Who created all the stars? He brings them out like an army, one after another, calling each by its name. Because of his great power and incomparable strength, not a single one is missing. . . . Have you never heard? Have you never understood? The Lord is the everlasting God, the Creator of all the earth. He never grows weak or weary. No one can measure the depths of his understanding.

Now, someone could object that the characteristics of God just established—that he is timeless, outside of space, matterless, and beyond the physical energy of the universe (from Evidence #1) and that he is a superintellect who fine-tuned the universe to precise measures in order to sustain life (from Evidence #2)—are some of the qualities normally attributed to God, but there is an important one missing: how can we know he's a morally good creator?

Fair question. Let's look at one more argument, this one from philosophy, which shows that God is not only the powerful and wise creator of the cosmos but also a morally good being who really does care about good versus evil, right versus wrong.

Evidence #3: Our Morally Good Universe

As an avid news watcher I often get depressed about the bad things that are happening in the world (and in my own city!). In Question 5, we'll address the problem of evil, focusing on how a good and loving God could allow pain and suffering to exist in the world. But what the news reports all too often overlook are the really good things that are happening in our midst.

Here are some examples of goodness I've come across recently:

A celebrity telethon (Hope For Haiti Now) raised $57 million in donations for the Haiti earthquake disaster.

Parents in Iowa adopted six young special-needs kids now that their biological children are nearly grown.

A Chicago man donated his kidney to save a local grocery store cashier whom he hardly knew.

A church in Indiana paid for a poor student's first year of tuition at a private college.

A group of California students devoted countless hours of work to help displaced children in Uganda.

The list could go on and on. There are countless ex­amples of goodness and virtue in our world. But a question arises: On what basis is something considered good or evil, right or wrong? And where did this basis come from? Did it start with the Big Bang? I can just imagine it: billions of years ago . . . massive explosion . . . galaxies emerging from the fiery blast. And then, out of the gaseous flames, "Thou shalt act altruistically; thou shalt be kind to the underprivileged; thou shalt love thine enemies; thou shalt not steal; and—oh yes—thou shalt maintain a moderately small carbon footprint" (all in perfect King James English, of course).

No one really believes that moral values emerge out of physical explosions. So where did they come from? Atheists are hard pressed to provide an answer for the existence of objective moral values. Look at what one atheist wrote in a recent article entitled, "Secularism's Ongoing Debt to Christianity":

Although I am a secularist (atheist, if you will), I accept that the great majority of people would be morally and spiritually lost without religion. Can anyone seriously argue that crime and debauchery are not held in check by religion? Is it not comforting to live in a community where the rule of law and fairness are respected? Would such be likely if Christianity were not there to provide a moral compass to the great majority? Do we secularists not benefit out of all proportion from a morally responsible society?

An orderly society is dependent on a generally accepted morality. There can be no such morality without religion. Has there ever been a more perfect and concise moral code than the one Moses brought down from the mountain?

Those who doubt the effect of religion on morality should seriously ask the question: just what are the immutable moral laws of secularism? Be prepared to answer, if you are honest, that such laws simply do not exist! The best answer we can ever hear from secularists to this question is a hodgepodge of strained relativist talk of situational ethics. They can cite no overriding authority other than that of fashion. For the great majority in the West, it is the Judeo-Christian tradition which offers a template.

We have, then, what is sometimes called the problem of good. The problem of good is a major challenge for atheism, for within the atheist view there simply is no way to explain or justify objective moral values.

When I read about or travel to other parts of the world, I'm often intrigued by the differences in etiquette. In India, many nationals do not use utensils to eat; they use their fingers instead. It would probably be rude in those contexts to whip out my travel mess kit and eat in front of them with fork and spoon. We should respect the differences in etiquette that have been created by various people groups and societies.

But morals and values are different from etiquette, and we all know it. They are not the creations of human beings. As we've said, they are objective, not relative—so they are above us and our particular laws and practices. If there were a culture, for example, that threw their firstborn male babies into the flames in order to gain the favor of the gods, this would be a morally dreadful act. If there were a culture in which men kept females as slaves and beat and raped them at will, we would be morally outraged. If there were a culture that locked up black people for their color or Jewish people for their heritage or left-handed people for their differentness, we would decry these actions as moral abominations.

If that culture's members objected to our indignation by saying that's just the way people do things in their culture—it's their tradition or custom or preference—we would flat-out reject their answer. We know that murder and rape and bigotry and racism are wrong—really, objectively wrong—regardless of traditions, customs, or preferences. But where did we get this knowledge—this intrinsic sense of right and wrong? If we didn't invent it, if it transcends the realms of culture and politics, if it's something we can't get away from, then what is its source? Could it be that a Moral Lawgiver actually knit those moral standards, along with the ability to understand and operate by them, into the very fabric of what it means to be human?

That conclusion certainly seems to square with logic and experience. It explains why we could boldly tell the Nazis that exterminating Jews was wrong and that they deserved to be punished for such wicked acts. And why we knew that Saddam Hussein was doing evil when he oppressed the Iraqi people, murdered his own family members, tortured and killed those he considered political threats, and ordered the gassing of thousands of Kurds. Our confident conviction about these matters—then and now—shows that morals are objective, not relative.

Unlike the atheist, the Christian has a solid basis for objective moral values, for in the Christian view, God exists as a supreme, transcendent, divine person—the Creator of the universe and everything in it. Goodness flows from God's very nature; moral values are not invented by human beings. They are discovered by human beings, but they are grounded in the very nature of a good, loving, personal God who made us in his image, implanted a sense of right and wrong in our hearts, and told us to live as imitators of him (see Eph. 5:1). Interestingly, this is also what the Bible tells us in Romans 2:15: "They demonstrate that God's law is written in their hearts, for their own conscience and thoughts either accuse them or tell them they are doing right."

This is powerful evidence for God. We can put this evidence in the form of a simple argument:

1. If God does not exist, then objective moral values do not exist.

2. But we know that objective moral values do exist.

3. Therefore, God does exist.

I'm not saying that atheists cannot recognize moral values or live generally moral lives. I'm certain they can. But recognizing something and even living by it does not mean that one has a real basis for it. The "moral" atheist is simply left hanging in midair on this issue, without any solid footing. Christians, on the other hand, have a rock solid foundation on which to build their beliefs and to live their lives. Our universe is morally good, and it's good because a transcendent and good God created it that way.

As we saw at the beginning of the chapter, God is like the virtue of love in this way: while we can't see love directly, we can often see evidence for it. The same is true about God. In addition to our own experience of him—which is important to talk about—we have looked at three kinds of evidence for him. These arguments provide solid reasons to believe in God: the existence of the universe, the amazing fine-tuning of the universe, and the reality of objective goodness. While each of these points to the existence of God, taken together they provide strong confirmationof his existence. We could sum it up like this: the cumulative case for God's existence is more than sufficient for an open-minded person to believe that he really is there.

God doesn't force his reality on anyone, but if our friends are interested in real evidence and answers, he has not left them wanting. God's fingerprints are dispersed throughout the cosmos. Maybe that's part of why Jesus told us so boldly in Matthew 7:7 to "keep on seeking, and you will find."

Summary of the Answer

Question 1 asks us, "What makes you so sure that God exists at all—especially when you can't see, hear, or touch him?"

We believe in many things that we don't see or directly experience with our senses—the virtue of love being a great example. Yet we see evidence of love through its effects. Similarly, we can't see God, but we can believe in him based on his work in us and in the universe around us.

One of the ways we can know that God is real and active in our world is that he's real and active in our lives—he's our friend! If that's true in your own experience, then talking about him will be a natural part of your answer to people who ask you this question about God's existence.

Evidence #1: Whatever has a beginning has a cause. Science shows us that the universe had a beginning. It therefore had a cause—one that's outside of itself and is therefore beyond time, space, matter, and physical energy. In other words, that cause has the characteristics of the God of the Bible.

Evidence #2: Our universe is fine-tuned, with astounding "just-so" precision, in ways that make it a place that can support life. The odds of this happening on its own, by sheer chance, are vanishingly small and thus point powerfully to an intelligent designer—One whom the Bible calls God.

Evidence #3: Apart from God there can be no objective moral standards. But we clearly live in a world that has objective moral standards. Therefore there has to be a divine moral lawgiver. We refer to that lawgiver as "God."

Our experience, science, and philosophy all point to the existence of an invisible God, One that fits the descriptions given in Scripture for Yahweh, the God of Abraham, Isaac, and Jacob—and of us, as Christians.

Tips for Talking about This Issue

Usually people who doubt God have a story to tell about how they got to that point. It's important to ask them questions and to respectfully listen to what they tell you, even though you'll probably not agree with everything they say. That's okay; James 1:19 says we need to "be quick to listen, slow to speak, and slow to get angry." Listening before speaking shows that you care about them, and it earns you the right to talk about your own beliefs.

It's almost a cliché to say that atheists are angry. But if your friends don't believe in God and do seem angry, ask why. Often you'll discover that something bad happened for which they blame God, the church, or a Christian. Listen with empathy and patience. Agree when you can, but also try to help them see that much of what's done in God's name or in religious circles is not from God but from imperfect people and institutions.

Share the answers and information in this chapter, but realize that helping people think in new ways is usually a slow process. Be patient, and be ready to explain it again and again or to talk about additional questions they might want to raise.

Realize there may be deeper personal issues—beyond what people are talking to you about—that hold them back from believing or trusting in God. These may be lifestyle issues, personal problems, hurts, prejudices, or misunderstandings about what Christians think and stand for. Pray for discernment and sensitivity in sorting out what the real issues are, and then address those issues.

Refer to the Bible's teachings in talking about your faith, but realize that many people don't accept its authority or truthfulness—especially those who question God's existence. Its message can still have power, but look to other sources of information to reinforce its truths (as we have in this chapter, with science and philosophy).

The Bible makes it clear that these discussions are not just about logic and good answers—but also about a spiritual struggle. Pray that God will direct your words and attitude and that he'll open your friends up to his love and truth.

Remember that love draws people, and disagreement can drive them away. So let love be your motivation, and be ready to back off if a conversation gets too heated or combative.

Questions for Group Discussion

1. Why might someone think you should believe only in things you can see, hear, or touch? What are some other things you believe in, in addition to love, that you can't see or experience directly through your senses?

2. What are some things you can talk about from your own experience that show you—and might convince your friends—that God really exists?

3. How does the fact that our universe had a beginning or the fact that it's fine-tuned with such exacting precision provide evidence for God?

4. Do you think there could be objective morality apart from God? From where would it draw its authority?

5. How has the evidence for God presented in this chapter affected your faith? Can evidence strengthen one's faith?

Mark Mittelberg is a best-selling author, a sought-after speaker, and a leading strategist in evangelism and apologetics-oriented outreach. He is the primary author of the Becoming a Contagious Christian training course, through which more than one million people around the world have learned to effectively and naturally communicate their faith to others. Mark was the evangelism director at Willow Creek for many years. He is a frequent contributor to Outreach magazine and a regular speaker for Church Communication Network (CCN.tv) satellite broadcasts to churches across North America. He was also an editorial consultant and periodic guest for Lee Strobel's Faith under Fire television show. He and Strobel have been ministry partners for more than 20 years.Excerpt used with permission.